Learning about Learning and Memory

July 15, 2013: How we learn and remember is a marvel to most of us and a long-standing fundamental problem for neuroscientists. Maya Ragini Overland shares the wonder.

“I want to understand the mechanisms that allow us to consolidate complex experiences into retrievable blocks of information,” she said. “I am fascinated that we can continue to learn and form new memories throughout our adult lives. How does that happen?”

Maya’s Science

“Our brains store new information by changing the strengths of the connections between neurons (brain cells). One way in which individual neurons achieve this is by altering the number of receptors they have available to sense the chemical neurotransmitter that is released into the synapses that connect them to other neurons in the network. We study a protein called Arc, which is important for the formation of long-term memories. I am trying to determine how Arc regulates the movement of a particular type of neurotransmitter receptor.”

Maya studies AMPA receptors, which enable the fast transmission of electrical signals between neurons in the central nervous system. To follow the movements of these receptors, Maya uses receptor components linked to pHluorin, a fluorescent protein that is sensitive to the acidity of its environment. When the receptors are at the cell surface, the pHluorin emits green light but, when the receptors are internalized into the more acidic “endosomes” inside the cell, the green signal is extinguished. By preventing cells from expressing a normal amount of Arc protein and watching how the signal from the pHluorin-tagged AMPA receptors changes in response to various drugs, Maya is trying to learn how Arc regulates the movements of specific subtypes of AMPA receptors away from the cell surface.

Maya is trying to find out. She is an MD-PhD student at UCSF is doing her thesis research in the laboratory of Gladstone Investigator Steve Finkbeiner. That research concerns a protein called Arc that is deeply involved in memory formation (see sidebar for a description of her work). Her PhD research is nearly complete and she will shortly return to medical school.

Learning is in Maya’s blood. Her mother has degrees in special education, design, and cultural anthropology. Her father spent 23 years as a professor of applied mathematics and computer science at Purdue University, the Indian Institute of Science, the Massachusetts Institute of Technology (MIT), the University of Pennsylvania, and Stanford.

“I lived in West Lafayette, Indiana for 8 years and in Bangalore, India for 9,” said Maya. “India felt a little foreign at first, and it took several years before I was at home there, but I wouldn’t trade the experience of living there for anything.”

Maya then began her own science education at MIT, but even then she continued to move around. She spent her junior year in Cambridge, England as part of an exchange between the MIT and Cambridge University physics programs. In 2003, Maya graduated from MIT with bachelor’s degrees in physics and biology and a minor in music composition.

“I went to MIT planning to major in biology but I really enjoyed physics. It’s hard to resist an intro physics professor who demonstrates simple harmonic motion by turning himself into a human pendulum and swinging across the front of the lecture hall!” she said. “However, I’d worked in developmental neurobiology labs at both MIT and Cambridge and remained more excited about the prospect of a career in biological research.” In the end, Maya’s accidental background in physics turned out to be fortuitous. She joined the biophysics department at UCSF for her PhD work and was supported by a graduate fellowship from the Fannie and John Hertz Foundation for research in applied physics.

Outside the lab, Maya continues to pursue her interest in learning. Since starting graduate school, she has learned to snowboard and to play the cello. And one more thing: she married.

“I took a few music classes to satisfy the humanities requirement at MIT and found that composing tonal music was like solving a fun logic puzzle. Here in San Francisco, I took up the cello again and have been playing with an amateur string orchestra.”

“Maya has unusual aptitudes in biophysics and quantitative biology and the ambition and creativity to tackle some of the most important and pressing problems in neuroscience,” said Dr. Finkbeiner. “I fully expect that she will become one of the leading scientists of her generation.”